At present

for the purpose of testing the breaking performance of commutated DC circuit breakers in the laboratory

power frequency synthetic test circuits are generally used

and the equivalence is to be discussed.This paper proposed a scheme for superimposing an oscillating current source to simulate an actual DC short-circuit current.For the DC system with design parameters of rated current 2 kA

short-circuit current 20 kA

and maximum current increase rate of 6 kA/ms

the relevant parameters of the low-frequency

high-frequency current source circuit and voltage source circuit were calculated respectively

and the overall system model was built by PSCAD.The time sequence of each module was analyzed

and the breaking test was successfully performed.It has certain reference value for the design of the actual DC circuit breaker and its test platform.